1. Field of the Invention
The present invention relates generally to the field of electromagnetic transmission devices such as optical or electrical transmission devices. More particularly, the present invention relates to an elongated element having at least one electrical and/or optical conductor and at least one additional element.
2. Description of the Related Art
Previously, communication networks have been organized in such a way that "intelligent" terminal devices are located at discrete locations. This may be, for example, at desks in offices, in computing centers, at service providers, in switching offices, etc. Discrete memories are then also located here in the form of hard disks, memory chips, magnetic cards, solid-state memories or similar devices. As a rule, lines are laid between these terminal devices to connect the devices. Various structures can thereby be used such as, for example, a star, tree, mesh or bus. Devices and amplifiers necessary for signal transmission or conversion are located at discrete locations between the terminal devices, depending on topology. The connections themselves are passive, consisting generally as a rule of copper wires, glass fibers or plastic fibers. The connection thereby respectively serves only as an end in itself.
It is for example known to insert amplifiers into the route of a line or of a cable. The cable is thereby interrupted in the region of the amplifier, and amplification is carried out in a separate structure (e.g., amplifier housing). Subsequently, a new cable piece is connected to the output of the amplifier, etc.
It is also known (WO 90/10879) to employ optical cables, which, in contrast to electrical cables, are very difficult to locate from the outside when buried. Externally permanent magnets may be attached at determined spacings, in order to locate the cables with a magnetic probe.
From DE 43 33 121 C2, a locating device is known having a magnetometer to locate magnetic objects in the ground. During a measurement, a person carrying out the measurement guides a magnetometer probe over the measurement path along a cord, whereby the measurement signals are retained by an electronic measurement device, taking into account the speed of the person carrying out the measurement. A plurality of detectable spaced emitters are provided on the cord, which respectively emit a path signal to the measurement device if the sensor passes over a spaced emitter of this type during the measurement. The emitters can also be realized in the form of electronic components in a chip, containing both the active electronic components and memory devices. When a spaced emitter is inserted, the cord is interrupted, and is led through a corresponding bore at the end side in the form of a loop.
From U.S. Pat. No. 5,045,368, a tube line (e.g., a gas line) is known for passing a flowing medium in which, for location in the buried state, marking means are arranged on the tube line in the form of passive electrical circuits which are tuned to a specific frequency. The marking means can be arranged in a predetermined pattern in order to obtain additional items of information. The individual marking means can be attached either to the line tube or can be successively strung on a cord.